Tests considered as recommended or not recommended by the Infectious Diseases Society of America (IDSA)/American Thoracic Society (ATS) and European Respiratory Society (ERS) guidelines
| IDSA/ATS recommendations | ERS recommendations | |
| Blood culture | Recommended in case of ICU admission, leukopenia, alcohol abuse, chronic severe liver disease, asplenia, positive pneumococcal urinary antigen test and presence of pleural effusion | Recommended in all patients hospitalised with CAP |
| Sputum culture | Recommended in case of ICU admission, alcohol abuse, severe obstructive or structural lung disease, positive Legionella urinary antigen test, positive pneumococcal urinary antigen test and presence of pleural effusion | Recommended in case of purulent sputum sample |
| Bronchoalveolar lavage culture | Recommended in case of intubation | Recommended in case of intubation |
| Legionella urinary antigen test | Recommended in case of ICU admission, alcohol abuse and presence of pleural effusion | Recommended in all patients hospitalised with severe CAP |
| Pneumococcal urinary antigen test | Recommended in case of ICU admission, leukopenia, alcohol abuse, chronic severe liver disease, asplenia and pleural effusion | Recommended in all patients hospitalised with severe CAP |
| Acute-phase serology for Chlamydophila pneumoniae, Mycoplasma pneumoniae, and Legionella species | Not recommended | Not recommended |
ICU: intensive care unit; CAP: community-acquired pneumonia.